Determining whether an individual is telling the truth or telling a lie has been a goal of humankind for centuries. Early methods of lie detection—as well as some modern techniques—rely on observations of proposed nonverbal indicators of deception, such as increased perspiration, changing body positions, or subtle facial expressions. However, there has been an effort to develop and use technology (i.e., the standard polygraph and infrared thermal imaging to aid in the identification of deception by measuring changes in sympathetic nervous system responses.
Of several techniques that are currently used and several others that are being developed to aid in the detection of deception, the standard polygraph examination is the most reliable (reliability, 80%-90%) and widely used. Although the polygraph test has become the most common method used to detect deception, it has several drawbacks. Functional magnetic resonance (MR) imaging based on blood oxygen level-dependent (BOLD) imaging is a method that is used to measure indirect responses that are tightly coupled with neuronal activity, and it is used to map human brain functions. This technique may enable accurate mapping of the regions of the brain that are involved in higher cortical functions, including cognitive processes such as deception and truth telling. Results of several functional MR imaging studies have shown the prefrontal cortices, parietal lobes, and anterior cingulate are activated during judgment, manipulation of information, and planning of response, including inhibition. None of these studies, however, used standard polygraph techniques or innovations from that field of expertise.
Other studies have been conducted that examine brain activity during deception and truth telling by using functional MR imaging and compare these results with the results of a standard polygraph examination [Mohamed, F. B., Faro, S. H., Gordon, N. J., Platek, S. M., Ahmad, H. A, Williams, J. M., Neuroradiology 238(2):679-688 (2006)].